Chapter 07: Human Birth Defects

Chapter 07: Human Birth Defects

Complete Chapter Questions With Answers

Sample Questions Are Posted Below

MULTIPLE CHOICE

Directions: Each group of questions below consists of a numbered list of descriptive words or phrases. For each numbered word or phrase, select the lettered part or heading that matches it correctly and then insert the letter in the space to the right of the appropriate number. Sometimes more than one numbered word or phrase may be correctly matched to the same letter.

1. ________ Webbed neck and short stature

ANS:   B

Webbed neck and short stature are associated with Turner syndrome (ovarian dysgenesis). These females have 44 autosomes and only 1 X chromosome. In the newborn period, these infants usually exhibit marked edema of the feet and webbing of the neck. The ovaries commonly consist of only connective tissue streaks. This condition is not recognized in many of these girls until they reach puberty (12 to 15 years), at which time they seek medical advice about primary amenorrhea (failure of menstruation to begin) and the lack of secondary sex development.

2. ________ Mental deficiency (retardation), low-set ears, and early postnatal death

ANS:   C

Infants with trisomy 18 have multiple major anomalies. Like those with the less common trisomy 13 syndrome, these infants have a severe mental defect and die during early infancy. Trisomy 18 is much more severe than Down syndrome, and females are more often affected (about 78% of these infants are female).

3. ________ Normal female appearance and usually fertile

ANS:   A

Most females with the triple X chromosome abnormality appear normal and are fertile. These women have two sex chromatin masses in their cells because of the presence of the extra X chromosome. Some triple X females have borne children, all of whom are normal and have normal karyotypes. Most females with four or more X chromosomes are also physically normal but severely retarded.

4. ________ Small testes and hyalinization of the seminiferous tubules

ANS:   E

XXY males appear normal at birth. Small testes and hyalinization of the seminiferous tubules are the constant characteristics of postpubertal XXY males with Klinefelter syndrome. The secondary sexual characteristics usually are poorly developed, and many of these males are tall and eunuchoid. Subnormal mentality is common